The Privacy Limits of Transacting in Bitcoin

The Bitcoin blockchain, a prime example of disruptive technology, has fundamentally altered the way various industries approach remote transactions. Bitcoin grants privacy to its users by anonymizing public keys, provides autonomy by eliminating the need for trusted third parties, and maintains transparency through its public disclosure protocol. Bitcoin is an innovative manifestation of the Fourth Amendment ideals of security and autonomy. It is, thus, no surprise that the Bitcoin blockchain presents unprecedented Fourth Amendment challenges for courts to consider. In United States v. Gratkowski, the Fifth Circuit addressed the novel issue of whether Fourth Amendment protections extend to an individual’s Bitcoin transactions. Notably, the court was the first to find that an individual does not have a privacy interest in their information located directly on the Bitcoin blockchain. However, the Fifth Circuit applied inconsistent and flawed reasoning in reaching this decision, demonstrating a fundamental misunderstanding of Bitcoin and its users. Accordingly, this Note argues that the Gratkowski decision should be applied narrowly and with caution, especially considering the Supreme Court’s warnings against the incompatibility of current Fourth Amendment doctrine with the digital age. It then suggests implementing a modified reasonable expectation-of-privacy standard, supplementing the current standard with an additional inquiry into what information an individual disclosed when initiating a transaction. This modified standard would preserve the integrity of Bitcoin, while simultaneously articulating a proper framework for assessing privacy concerns in the context of Bitcoin and blockchain technology.